Solar Car Data Collection Solar Car Data Collection SystemSystem

Matt BoydenMatt Boyden

Rene DupuisRene Dupuis

Ryan LavalleeRyan Lavallee

4/23/08

RyanRyan

BackgroundBackground

Building miniature solar Building miniature solar cars is a very common cars is a very common activity for teaching activity for teaching school-age kids about school-age kids about renewable energyrenewable energy

There are events There are events specifically designed for specifically designed for building and racing solar building and racing solar cars that are available as cars that are available as educational kitseducational kits

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Project DescriptionProject Description

What is needed is a small, light data logging What is needed is a small, light data logging device specifically designed to interface with device specifically designed to interface with a typical educational solar car kit.  a typical educational solar car kit. 

The data collection system will collect data The data collection system will collect data on voltage, current and speed, every ½ on voltage, current and speed, every ½ second. second.

The data will allow educators to output The data will allow educators to output graphs of distance, speed, acceleration, graphs of distance, speed, acceleration, voltage, current, power and energy vs. time. voltage, current, power and energy vs. time.

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Project RequirementsProject Requirements

Record voltage and current to the motor for Record voltage and current to the motor for a specific amount of timea specific amount of time

Interface with a computer to easily output Interface with a computer to easily output the information in a way that can be used the information in a way that can be used for educational purposesfor educational purposes

The product must be light enough and use The product must be light enough and use little power so as not to significantly change little power so as not to significantly change the performance of the carthe performance of the car

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System DiagramSystem Diagram

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System Diagram Data System Diagram Data CollectionCollection

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System Diagram Data OutputSystem Diagram Data Output

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Design OutlineDesign Outline

Speed, Current and Voltage SensingSpeed, Current and Voltage SensingMicrocontroller ProgrammingMicrocontroller ProgrammingThe User InterfaceThe User InterfaceCircuit Board Design and LayoutCircuit Board Design and LayoutEnclosure DesignEnclosure DesignProject ManagementProject Management

Speed, Current, and Speed, Current, and Voltage SensingVoltage Sensing

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Velocity Sensor ConceptVelocity Sensor Concept Every time the wheel rotates the sensor triggers the Pulse Accumulator in the microcontroller By knowing the wheel circumference and reading the accumulator value at regular time intervals we can calculate the speed of the car

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Reflective Object SensorReflective Object Sensor

Consists of an infrared emitting Consists of an infrared emitting diode and NPN silicon diode and NPN silicon phototransistor mounted side phototransistor mounted side by sideby side

Phototransistor responds to Phototransistor responds to radiation emitted from diode radiation emitted from diode when it senses a reflective when it senses a reflective devicedevice

Provides Provides High output sensing no High output sensing no

reflectionreflection Low output sensing Low output sensing

reflectionreflection

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ComparatorComparator

Velocity sensor output runs Velocity sensor output runs into comparatorinto comparator

Eliminates hysteresis and Eliminates hysteresis and rise times when changing rise times when changing states (high to low; low to states (high to low; low to high)high)

Provides quick transition Provides quick transition intervals as comparator intervals as comparator changes stateschanges states

Provides sure outputProvides sure output

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Comparator SimulationComparator Simulation

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Velocity Sensor CircuitVelocity Sensor Circuit

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Current SensingCurrent Sensing Use Resistor to measure Use Resistor to measure

current to motorcurrent to motor 0.150.15ΩΩ resistor will not affect resistor will not affect

motor performancemotor performance Easy to install in series with Easy to install in series with

clip leadsclip leads Voltage will be amplified Voltage will be amplified

x30 and converted to x30 and converted to positive voltage before A-D positive voltage before A-D converterconverter

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Voltage SensingVoltage Sensing

Voltage will be read Voltage will be read directly off of the directly off of the panel with an A-D panel with an A-D convertor.convertor.

The voltage and The voltage and current values will current values will also be used to also be used to calculate power and calculate power and energyenergy

Microcontroller Microcontroller ProgrammingProgramming

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Microcontroller ProgrammingMicrocontroller Programming

We will use a Motorola HC12 We will use a Motorola HC12 microcontrollermicrocontroller

What does the Program have to doWhat does the Program have to doData Transmission to PCData Transmission to PC

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The HC12The HC12

Has Analog to Digital ConvertersHas Analog to Digital ConvertersHas RS232 Chip Built into ModuleHas RS232 Chip Built into Module16kB Flash Memory for Data16kB Flash Memory for DataEasily programmed using available Easily programmed using available

softwaresoftwareCan be programmed on docking module Can be programmed on docking module

then transferred to applicationthen transferred to application

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Program RequirementsProgram Requirements

→ On Request: On Request: → Read Data from A2D Ports (Voltage and Current)Read Data from A2D Ports (Voltage and Current)→ Read Data from Wheel Sensor (Speed)Read Data from Wheel Sensor (Speed)→ Store Data to Flash MemoryStore Data to Flash Memory

→ On Request or Timeout:On Request or Timeout:→ Stop Recording DataStop Recording Data

→ On Request:On Request:→ Transfer Data to ComputerTransfer Data to Computer→ Erase MemoryErase Memory

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Data TransmissionData Transmission

Current, Voltage and Speed information is Current, Voltage and Speed information is sent one number at a time through an sent one number at a time through an RS232 connectionRS232 connection

We are using Hyper Terminal to receive We are using Hyper Terminal to receive the data and capture it to a text file the data and capture it to a text file

From here, the data will be available on a From here, the data will be available on a PC to be accessed by the VBA programPC to be accessed by the VBA program

The User InterfaceThe User Interface

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PC ProgrammingPC Programming

How the Excel How the Excel Program WorksProgram Works

User InterfaceUser Interface OutputsOutputs

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How VBA Program worksHow VBA Program works

Program references .txt fileProgram references .txt file Places .txt file in predefined rowsPlaces .txt file in predefined rows Excel programmed to make calculations and Excel programmed to make calculations and

produce graphs of all the dataproduce graphs of all the data Calculations: Calculations:

Voltage Cell: A2D_V * 0.0049Voltage Cell: A2D_V * 0.0049 Current Cell: ((A2D_I*0.0049)/30)/0.15Current Cell: ((A2D_I*0.0049)/30)/0.15ΩΩ Velocity: Velocity: (PA(t) – PA(t-1)) * Wheel circumference(PA(t) – PA(t-1)) * Wheel circumference

0.5 seconds 0.5 seconds

Automates graph wizard process for all dataAutomates graph wizard process for all data

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User InterfaceUser Interface

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OutputsOutputs

Each graph will be displayed on a Each graph will be displayed on a separate page in Excelseparate page in Excel

Circuit Board Design and Circuit Board Design and LayoutLayout

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Board Layout MethodologyBoard Layout Methodology

CircuitCircuit

This is the circuit board that we designed. This will contain the Microprocessor, and any circuitry required. This board must be small enough to fit on the solar car and as light as possible.

Case DesignCase Design

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DesignDesign

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Design DimensionsDesign Dimensions

Project ManagementProject Management

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ResponsibilitiesResponsibilities Ryan Ryan

Data Retrieval (PC Data Retrieval (PC end)end)

Excel VBA Excel VBA ProgrammingProgramming

Circuit board layoutCircuit board layout

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conditioningconditioning HC12 HC12

programming,programming, Data Data

transmission to transmission to PC (HC12 end)PC (HC12 end)

• ReneRene• Wheel sensing Wheel sensing

designdesign• Power Power

DistributionDistribution• Casing PrototypeCasing Prototype• WebsiteWebsite

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ScheduleScheduleWeek 1 2 3 4 5 6 7 8 9 10 11 12 13 14TaskProgramming HC12:Flowcharts MRead Data M M MStore to Flash M M MTransmit Data to Computer M M M

Excel Programming:Read from .txt File J JOutput Graph J J J

Sensor Selection:Define Options R RCollect Data Sheets R RChoose Wheel Sensor R RChoose Current Sensor MR MR MR

Battery Selection:Select a battery to power HC12 R R

Circuit Layout:Build Circuit on Breadboard M M MRun Circuit to Record Data M M MDesign PCB M M MMake First PCB M M

Wheel Sensor:Sensor Design/Selection R R R JR JR JRWheel Sensor Data Collection: M M M M MTransfer Wheel Data Into Speed JM JM JM JM JM

Design Casing:Casing Design MR MR MR MRCasing Prototype R R RFinal Case Production R R

Manuals/Instructions:Manual/Instruction Writing MJR MJR MJR MJR MJR

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BudgetBudgetItemItem CostCost Actual Actual

CostCost

HC12HC12 $30$30 $0$0

Solar CarSolar Car $50$50 $50$50

Reflective SensorReflective Sensor $2.86$2.86 $0$0

3V Lithium Battery 3V Lithium Battery (2)(2)

$1.98$1.98 $0$0

Op-ampOp-amp

TLV 2772 (3)TLV 2772 (3)

$6.75$6.75 $6.75$6.75

Ribbon Cable(2)Ribbon Cable(2) $10.00$10.00 $10.00$10.00

ComparatorComparator $1.74$1.74 $1.74$1.74

Resistors, LEDs, Resistors, LEDs, Pushbuttons etcPushbuttons etc

$20.00$20.00 $0$0

TOTALTOTAL $123.33$123.33 $68.49$68.49

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Next Steps in the Design ProcessNext Steps in the Design Process

Write our own communications program Write our own communications program instead of using Hyper Terminalinstead of using Hyper Terminal

Finalize casing with smaller and lighter Finalize casing with smaller and lighter componentscomponents

Use ‘power saving’ options on HC12 to Use ‘power saving’ options on HC12 to lower power consumption and improve lower power consumption and improve battery lifebattery life

Meet with educatorsMeet with educators

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Questions?Questions?

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